he does not look bad, but he does not look amazing either ? , mostly I would ask that you try and complete some other peices, what it looks here is as if you just primed him black, and drybrushed ? or basecoated the model dark angel green.
I dont know if you tried doing some highligths by outlining the armour but generaly people but a dab of either white paint, or use a color thats slightly lighter to outline the edges.
Besides that he's missing some stuff , try to "complete" him per say, and then come back with a result

unless there is a specific piece of the model you would want somebody to grade.
I don't know about you but when I have to paint 30 orks or more, I generaly finish (in no particular order) skin 1st , then guns, than pants , teeth, etc.
For space marines its ultimately up to the painter, either you do all armour 1st , then guns, most importantly have fun! and just get a minature completely finished to the best of your abilities, the 1st model is always best since you remember what you painted it like forever

and obviously you can see your progress with time passing.
Have Fun !